Coordinate Measuring Machine - Patent 8091248

The present invention relates to a coordinate measuring machine, particularly of the horizontal arm type.BACKGROUND ART Coordinate measuring machines of the aforesaid type are known, comprising a base provided with guides along which a first horizontal axis X, a first carriage mobile on the base along the axis X and comprising an upright provided with guidesextending along a second vertical axis, a second carriage carried by the upright and sliding on the same along axis Z, and an arm carried by the second carriage and extending along a third horizontal axis Y orthogonal to the axis X. One end of the arm isadapted to carry a contact or optical detector for measuring the dimensional features of parts. In the known machines of the type briefly described, the guides of the first carriage along the axis X are normally arranged on an upper surface of the base, and the first carriage is provided with runners sliding on the guides. The upper surface of the base therefore presents a discontinuity due to the aforesaid guides. Furthermore, the guides must be adequately protected to prevent dirt from depositing on the same, or foreign bodies from reaching the guides and interacting with the runners of the first carriage. The known protection systems generally consist of a flexible ribbon arranged so as to cover the guides. The ribbon is lifted by the first carriage as it transits, by means of diverting members, allowing the runners of the first carriage toslide on the guides. This system, however widely used, is complex and costly. Furthermore, the ribbon does not constitute a rigid, treadable surface and may be damaged. Finally, the structure itself of the base is complex and costly.DISCLOSURE OF INVENTION It is the object of the present invention to make a coordinate measuring machine which allows to solve the problems related to the known machines specified above. This object is achieved by a measuring machine according to claim 1. BRIEF DESCRIPTION OF THE DRAWINGS For